Windshield



J. A. JOHNSON WINDSHIELD Filed Jan. 30, 1929 May 13, 19:10.

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INYENTOR JACK A JOHNSON /8 BY ATTORNEY Patented May 13, 1930 UNITEDSTATES PATENT OFFICE JACK A. JOHNSON, OF ROBBINSDALE, MINNESOTA WINDSHIELD This invention relates to Windshields for motor vehicles and theprimary object is to provide means of a novel, efficient, and practicalnature for preventing the accumulation of ice, frost, or condensation onthe windshield to obstruct the drivers vision. More specifically theinvention comprises an electric heating or hot wire system, in whichhigh resistance circuit controlled Wires are imbcdded or inserted in thewindshield proper, so that the glass thereof may be heated, at will,under which circumstances its surfaces will remain relatively clearregardless of weather conditions and diiierences in, temperature insideand outside of the car.

in the accompanying drawing, illustrating a preferred embodiment of myinvention Fi 1 is perspective elevation of a windshield unit embodyingmy invention, fractional portions being broken away for purpose oiillustration.

Fig. 2 is an enlarged sectional detail view on the line 22 in 1.

Fig. is a diagrammatic illustration of the circuit control systememployed.

Referring to the drawing more particularly and by reference characters Adesignates the glass of a windshield having a frame B. This frame may beof any suitable construction although. a frame that is channel shaped incross section, as shown, is best adapted in the present instance.

Extending horizontally through the glass A is a series of verticallyspaced high resistance wires 4, 5, 6, and 7, terminating at the sideedges of the glass in insulating terminal plugs 8. The wires 4l-7 maybemerely secured between two sheets of glass, but I prefer to imbed themin the body of a single pane. In either event the plugs 8 are intendedto serve the double purpose of con nections between the wires l7 and themain circuit wires, and also to fit tightly in place to exclude air fromreaching the wires 4-7. It is also preferable to place a semi-tubularinsulation guard 9 over the circuit wires run-- ning up into the endposts of the frame 13.

The left ends of the wires 4 and 6 connect directly with one pole of asource of current, as a battery 10, by circuit wires 11 and 12,resoectively, the other pole of the battery being grounded as at 13. Theleft ends oi the wires 5 and. 7 are connected by circuit wires 14. and15, respectively to the terminal 16 oi a switch 17, grounded as at 18.The wires 45 and 67 are connected in pairs. at their right ends. byshort wires 19 and 20, and these wires are in turn connected by wires 21and 22, respectively, to a second terminal 23 of the switch 17 As shownin Fig. 3, the switch 17 is in an open position, This switch is ofcourse placed in a convenient position in the car for operation by thedriver.

lVhen the switch is closed to terminal 16 currents are caused to flowthrough the two circuits 1o, 11, 4, 19. 5, 14, 1e, 17, 1s, 13, and 10,12, 6, 20, 7, 15. 16, 17, 18, 13, thus causing all the wires 417 tobecome heated, and this heat is in turn spread quite uniform-- lythroughout the class A. Should it be desired to confine the currents tofewer oi? the wires 47, and thus more restrict the heating areas, butpermit the application oi a more ellective current flow, the operatorcloses the switch 17 to the terminal The two previously describedcircuits are now open while new circuits are respectively closed throughelements 10, 11, 1, 19, 21, 23, 17, 18, 13, and 10, 12, 6, 20, 22, 23,17, 18, 13, thus only heatingthe resistance wires 4 and. 6.

It is of course understood that the invention may be applied to windows,other than Windshields, if so desired. It is further understood thatsuitable modifications may be made in the mechanical and electricaldesign and arrangements, as herein set forth, without departing from theinvention, as such, provided, however, that such modifications comewithin the spirit and scope of the appended claim.

Having now therefore illustrated and described my invention, what Iclaim to be new and desire to protect by Letters Patent is:

The combination with the pane of a Windshield or the like, of verticallyspaced heating wires imbedded in and extending horizontally through thepane for heating the same, and terminal plugs, for the wires, ilnbeddedin the end edges of the pane.

Signed at Minneapolis, Minnesota, this 28th day of January, 1929.

JACK A. JOHNSON.

